A pilot aboard an American Airlines flight headed for Boston died on Monday, the airline has confirmed.

The flight, an Airbus A320 carrying 147 passengers and five crewmembers, had been redirected to Syracuse after 7 a.m. for a medical emergency. It had been scheduled to land in Boston after leaving from Phoenix around midnight this morning, a spokeswoman for American Airlines said.

In a statement, the airline could not say what caused the pilot’s death, but said the plane had been directed “due to pilot illness.”

“Unfortunately, our pilot passed away. We are incredibly saddened by this event, and we are focused on caring for our pilot’s family and colleagues,” the statement said.

The statement also said an American Airlines replacement crew had been sent to take diverted passengers to their destination in Boston.

The pilot had not been identified.

A cause of death had not been made public and a spokesman for the Syracuse Police Department said around 1:40 p.m. that the pilot's death remained under investigation.

According to multiple reports, passengers on the flight arrived safely in Boston around 1 p.m.